Replaceable tool for electrochemical drilling

ABSTRACT

A replaceable tool for an electrochemical drilling operation in which several electrodes are supported by a base that is mounted as a unit on a tool support and has arrangements for connecting to the electrical supply and to the supply of electrolyte.

United States Patent 1 Shaw 1 Oct. 23, 1973 [54] REPLACEABLE TOOL FOR3,668,105 6/1972 Abt 204/297 R ELECTROCHEMICAL DRILLING 3,314,875 4/1967q 3,421,997 1/1969 WIlhams 204/284 Inventor: Richard H. Shaw, Hampden,Mass.

United Aircraft Corporation, East Hartford, Conn.

Filed: Oct. 18, 1971 Appl. No.: 189,862

Assignee:

References Cited UNITEDISTATES PATENTS 3/1973 Cross et a1. 204 29'/ R xPrimary Examiner-John H. Mack Assistant Examiner-D. R. ValentineAtt0rneyCharles A. Warren [57] ABSTRACT A replaceable tool for anelectrochemical drilling operation in which several electrodes aresupported by a base that is mounted as a unit on a tool support and hasarrangements for connecting to the electrical supply and to the supplyof electrolyte.

7 Claims, 4 Drawing Figures mimtnumsma 3.751.555

- SHEET 10F 2 PMENTED 0C! 2 3 i913 SHEET 2 OF 2 REPLACEABLE TOOL FORELECTROCHEMICAL DRILLING BACKGROUND OF THE INVENTION In multipleelectrode drilling, long individually mounted tubular electrodes areheld in an electrically conductive manifold and supported near the workby suitable guides. The connections at the manifold and in the guidesare difficult to make secure without leakage and without damage tothe'electrode. Further, replacement of a damaged electrode requiresexcessive *down time for the machine.

SUMMARY OF THE INVENTION One feature of this invention-is an-electrodeassembly which serves-to support a plurality of electrodes inpredetermined relation to one another and which is positioned as a unitwithin the electrochemical drilling machine. Another feature is thearrangement of the support for the assemblage of electrodes such thatconnection is made with the electrical supply and with the supply ofelectrolyte when the support is positioned on the machine.

According tothe invention, a baseof suitable dielectric material shapedto fit removably in a recess in the electro-chemical machine supports atleast one electrode therein and preferably a plurality of'electrodes inpredetermined relation to one another with the base providing aconnection whenpositionedin the machine from the electrolyte supply tothe electrodes and an electrical connection from the source ofelectricity to the electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1.

FIG. 3 is a perspective view of the device. FIG. 4 is a perspective viewof a mold element used in making the tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT The machine shown in FIG. 1 hasa base on which a work support 12 is mounted for supporting a workpiece14 therein. The work support is adapted for positioning on the base formovement in ahorizontal plane so that the workpiece may be properlypositioned below the electrodes 16 which serve to'drill the desiredholes in the workpiece.

Positioned above the work support and also carried by the base is a toolsupport structure which includes a support 18 on which a slide 20 ismounted for horizontal movement. The slide may incorporate stop means 22for accurately positioning the slide in predetermined relation to theworkpiece mounted below. The slide carries a bracket 24 which has adovetail slot 26, FIG. 2, therein to receive the replaceable tool 28,FIG. 2. The slide 20 has a connection 30 for attachment to a supply ofelectrolyte and this electrolyte is directed through a passage 32 in theslide-and a cooperating passage 34 in the bracket 24. The passage 34terminates in a cylindrical recess 36 positioned horizontally in thebracket and this recess36 receivesa portion of the replaceable tool aswill be apparent.

The replaceable tool as shown in FIGS. 2 and 3 includes a base 38 inwhich are embedded the plurality of electrodes 16 except for theoperative ends of these electrodes and except for a tube 42'with whichthe hollow electrode communicate. The :tube 42 extends beyond the base38 and is received in the recess 36 as shown in FIG. 1. A suitable seal'44 provides a fluidtight connection for the tube 42 within the recess36. In alignment withthe recess 36 is a slightly larger recess 46 andthis recess has an electrical spring connection 48 therein to engagewith the surface of the tube 42 when it is in the operative positionshown in FIG. 1 thereby making an electrical connection through thebracket 24 from the electrical supply 50 to the tube 42 and thence tothe electrodes 16.

As shown in FIG. 2, when the tool 28 is in position in the machine, itis held in this position as, for example, by a clamping screw 52 locatedin the bracket 24. The dovetail slot in the bracket locates thereplaceable tool in precise relation to the workpiece, the latter beinglocated beneath the tips of the electrodes forming part of thereplaceable tool.

In making the replaceable tool, the tube 42 has the necessary number ofholes drilled therein to accept the several electrodes 16 and, when theelectrodes are inserted into the tube through the formed holes, theseelectrodes are secured in the tube by a suitable conductive sealer whichin addition to supporting the electrodes securely in position in thetube also serves to provide a good electrical contactbetween the tubeand the electrodes. It is desired to have the ends of electrodes projectthrough the wall of the tube and slightly into the central passage inthe tube as shown in FIG. 1. If the electrodes have a dielectric coatingon the outer surface, this coating is removed in the area of the tube 42to assure a good electrical contact.

After the tube and electrodes are assembled, they are supported in amold part 54, FIG. 4. A similar mating part, not shown, cooperates withthis part in forming the complete mold. This mold part has guidepassages 56 located adjacent to the operative tips of the electrodes tosupport them in precise relation to one another and also has atransverse guide passage 58 to receive the tube 42. The mold part 54 hasa recess 60, and when the mating mold parts are assembled, thecooperating recesses form a cavity into which the material forming thebase 38 is poured to form an enclosure for a part of the tube and forthe portion of electrodes between the tube and the operative tips. Thematerial for the baseis preferably a low exothermroom-temperature-curing vacuum-degassed, epoxy resin. This resinsolidifies to form a base of the appropriate shape with the dovetailconfiguration adjacent the tube 42 to fit within the machine as abovedescribed, and to make sure of the-proper location of thetube in therecess 36.

By using a mold of the type shown and thereby precisely locating theopen end of the tube 42 within the surrounding base, it will be apparentthat when this replaceable tool is positioned in the machine as shown inFIG. 2, this open end of the tube will engage a shoulder '62 at the endof the recess 36 so that the electrodes 16 will be located and supportedin the precise position for drilling the desired holes in the workpiece.The outer end of the tube 42 is'closed by a cap 64 which has a smallopening 66 therein to provide a continuous air bleed so that there is acontinuous gas-free supply of electrolyte to the electrodes when thedevice is in operation.

Should the tip of one of the electrodes 16 be damaged in any way, thedamaged tool with the damaged electrode thereon is readily withdrawnfrom the machine and a new undamaged tool as readily placed in positionso that the machine can continue in operation with no significant lossof time. The replacement of the tool necessitates only the release ofthe holding screw 52 to permit the damaged tool to be slid out of thedovetail slot and a new one positioned therein. The positioning of thenew tool also makes the desired electrical and electrolyte connectionsso that the machine may be immediately put back in use.

The base for the tool is so contoured adjacent the operative ends of theelectrodes as to permit the operator of the machine to see readily theprogress of the drilling operation and at the same time provide asuitable support for the several electrodes.

I claim:

1. A replaceable tool for an electrochemical drilling machine having atool receiving recess with guiding surfaces therein, and an electrolytesupplying passage parallel to said guiding surfaces, said toolincluding:

a base of dielectric material shaped to fit removably in said recess andhaving guiding surfaces cooperating with the guiding surfaces on themachine,

a tube in said base and having a projecting end to receive electrolyte,said tube extending from said base in parallel relation to said surfacesand positioned to engage said passages,

at least one electrode in said base substantially at right angles to thetube and having one end intersecting said tube within the base,

the operative end of the electrode projecting from said base and beingsupported thereby in operative position for a drilling operation.

2. A replaceable tool as in claim 1 in which a plurality of electrodesare positioned in and supported by said base in parallel relation to oneanother and all intersecting said tube for drilling a plurality of holessimultaneously.

3. An electrochemical drilling machine having a work support,

a tool support in predetermined relation to said work-piece support andmovable relative to said workpiece support for performing a drillingoperation,

tool mounting guide means on said tool support, and

electrolyte supply means in parallel relation to the guide means on saidtool support, in combination with,

a tool having a dielectric base with cooperating guide means to engagereleasably with said tool mounting guide means,

a plurality of electrodes within and supported by said base and havingprojecting tips in a position to perform a drilling operation on aworkpiece on said work support, and

an electrolyte tube in said base intersecting with said electrodes tosupply them with electrolyte, said tube being supported by said base inparallel relation with said cooperating guide means in a position toengage said electrolyte supply means when said base is positioned onsaid tool mounting means.

4. A machine as in claim 3 in which the tool support has electricalcontact means in a position to engage the tube when the base ispositioned on the tool mounting means.

5. A machine as in claim 3 in which the tube extends beyond the base,and the electrical contact means engage with said tube extension whenthe base is positioned on said tool mounting means.

6. A replaceable tool for use on an electrochemical drilling machinehaving tool guide means thereon and an electrolyte supply passage havingits axis parallel to and in fixed relation to the guide means, said toolincluding a dielectric base having guide means to cooperate with saidtool guide means on the machine,

a tube in said base in parallel relation to the guide means thereon andhaving a projecting open end in such fixed relation to the guide meanson the base as to enter said electrolyte supply passage when the tool ispositioned on the machine, and

a plurality of parallel hollow electrodes within the base having theiroperative ends projecting therefrom and all intersecting with said tubeto receive I electrolyte therefrom.

7. A tool as in claim 6 in which the base is nonconductive, the tube andelectrodes are conductive, and the projecting end of the tube engages anelectrical contact on the machine adjacent to the electrolyte supplypassage.

1. A replaceable tool for an electrochemical drilling machine having atool receiving recess with guiding surfaces therein, and an electrolytesupplying passage parallel to said guiding surfaces, said toolincluding: a base of dielectric material shaped to fit removably in saidrecess and having guiding surfaces cooperating with the guiding surfaceson the machine, a tube in said base and having a projecting end toreceive electrolyte, said tube extending from said base in parallelrelation to said surfaces and positioned to engage said passages, atleast one electrode in said base substantially at right angles to thetube and having one end intersecting said tube within the base, theoperative end of the electrode projecting from said base and beingsupported thereby in operative position for a drilling operation.
 2. Areplaceable tool as in claim 1 in which a plurality of electrodes arepositioned in and supported by said base in parallel relation to oneanother and all intersecting said tube for drilling a plurality of holessimultaneously.
 3. An electrochemical drilling machine having a worksupport, a tool support in predetermined relation to said work-piecesupport and movable relative to said workpiece support for performing adrilling operation, tool mounting guide means on said tool support, andelectrolyte supply means in parallel relation to the guide means on saidtool support, in combination with, a tool having a dielectric base withcooperating guide means to engage releasably with said tool mountingguide means, a plurality of electrodes within and supported by said baseand having projecting tips in a position to perform a drilling operationon a workpiece on said work support, and an electrolyte tube in saidbase intersecting with said electrodes to supply them with electrolyte,said tube being supported by said base in parallel relation with saidcooperating guide means in a position to engage said electrolyte supplymeans when said base is positioned on said tool mounting means.
 4. Amachine as in claim 3 in which the tool support has electrical contactmeans in a position to engage the tube when the base is positioned onthe tool mounting means.
 5. A machine as in claim 3 in which the tubeextends beyond the base, and the electrical contact means engage withsaid tube extension when the base is positioned on said tool mountingmeans.
 6. A replaceable tool for use on an electrochemical drillingmachine having tool guide means thereon and an electrolyte supplypassage having its axis parallel to and in fixed relation to the guidemeans, said tool including a dielectric base having guide means tocooperate with said tool guide means on the machine, a tube in said basein parallel relation to the guide means thereon and having a projectingopen end in such fixed relation to the guide means on the base as toenter said electrolyte supply passage when the tool is positioned on themachine, and a plurality of parallel hollow electrodes within the basehaving their operative ends projecting therefrom and all intersectingwith said tube to receive electrolyte therefrom.
 7. A tool as in claim 6in which the base is nonconductive, the tube and electrodes areconductive, and the projecting end of the tube engages an electricalcontact on the machine adjacent to the electrolyte supply passage.